This type of apparatus has widely been known as an apparatus which has a platen to place an original document image in an apparatus casing, and guides reflected light of light applied from a light source to an imaging device by a reading optical system to perform photoelectric conversion.
Then, inside the casing are disposed a plurality of boards such as a power supply board for supplying power to a light source lamp, a sensor board for controlling a photoelectric converter, a control board for controlling scanning operation of image reading, and an image processing board for performing signal processing on read data. Then, these boards are disposed, while being stacked in a layered shape inside the casing.
For example, in Patent Document 1, a plurality of boards is disposed inside a casing, while being spaced a distance apart, and a cooling fan is disposed in each board to form a flow of cooling air from one end to the other end. In the Document, cooling air is sent to a heat sink integrally attached to the board.